A convential tenter arm swinging apparatus is generally constructed in such a way that a nut secured to a tenter arm is threadedly connected to a screw shaft rotatably journalled in the vicinity of the front of the arm, and the screw shaft is adapted to be rotated by swinging means disposed outside the apparatus and comprising a screw shaft rotating pulley, a transmission belt and a reversible rotatable motor, and the rotation of the screw shaft causes the nut to be transversely moved to swing the arm.
According to such conventional apparatus, since the swinging means is disposed outside the apparatus, it is inevitable that the whole apparatus becomes quite large, so that a broad space for installation is required.
There is another installation problem in that the component elements should be arranged to take spatial conditions ouside of the apparatus into account; for example, the screw shaft bearing portions and the motor should be mounted to the frame, respectively, to take the transmission belt travel distance into account.